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Topic: Sound power level

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Sound power

Sound intensity level

Sound pressure level

Particle velocity level

Particle velocity

Sound intensity

Sound energy flux

Sound

Speed of sound

Acoustics

Sound impedance

Common logarithm

Characteristic impedance

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	Sound Power Level
		In addition to the sound pressure level, there are other levels expressed in decibels, so one must be careful when reading technical articles about sound or regulations on environmental noise.
		Sound power, like electrical power, is measured in watts.
		The sound power level (in decibels) is defined as :
	personal.cityu.edu.hk /~bsapplec/sound1.htm (96 words)

	Sound power level Encyclopedia (Site not responding. Last check: )
		Sound power level or acoustic power level is a logarithmic measure of the sound power in comparison to a specified reference level.
		One of the advantages of expressing the noise level of a source in terms of its power level is that one does not have to note any distance from the source.
		The most common means is measuring the sound power level from the speaker with the measuring device placed directly in front of and one meter away from the source.
	www.hallencyclopedia.com /topic/Sound_power_level.html (694 words)

	Sound Power and Intensity
		For a sound wave, the amount of energy transported is proportional to the square of the amplitude of the wave.
		Both sound pressure level and sound intensity level are purported to measure the same thing: the loudness of a sound that we hear.
		The next step to show the equality of sound pressure level and sound intensity level is to realize that the intensity in a sound wave is proportional to the square of the amplitude of the sound wave.
	hep.physics.indiana.edu /~rickv/Sound_intensity.html (912 words)

	Noise and Hearing Conservation Technical Manual Chapter: Noise and Health Effects (App I:A-3) (Site not responding. Last check: )
		However, the sound pressure level at some distance (r) from the source is dependant on that distance and the sound-absorbing characteristics of the environment.
		Sound Power (W) is the amount of energy per unit time that radiates from a source in the form of an acoustic wave.
		This distribution of sound power over the area of the propagating wave is designated as intensity and is measured in units of watts per square meter.
	www.osha.gov /dts/osta/otm/noise/health_effects/soundpropagation.html (827 words)

	Turbine Lw Estimation
		The sound power test was conducted during the performance test of the equipment.
		Typical sound pressure measurements could not be used to determine the sound power of the turbine.
		The sound power emission was calculated using an acoustic intensity method as described in ISO 9614-2, "Acoustics - Determination of sound power levels of noise sources using intensity - Part 2: Measurement by scanning".
	www.navcon.com /CaseStudy_8.htm (166 words)

	Help Topics - S
		Measurement of the sound exposure levels of different noise sources allows their contribution to the overall noise climate to be easily compared since all results are referenced to the same time interval of 1 second.
		The level is expressed in decibels relative to the reference pressure level and unless specified to the contrary is normally taken to be the A weighted level.
		Sound level meters can be battery operated for field use or can be powered from external power sources depending upon their power consumption and the length of time required for autonomous operation.
	www.casellausa.com /en/help/help_s.htm (1603 words)

	Sound power - Biocrawler (Site not responding. Last check: )
		of a source is expressed in decibels (dB) and is equal to 10 times the logarithm to the base 10 of the ratio of the sound power of the source to a reference sound power.
		Sound power is neither room dependent nor distance dependent, like it is with sound pressure or sound intensity.
		Usable music sound (trumpet) and noise sound (excavator) have both the same sound power of 0.3 watts, but will be judged psychoacoustically to be different levels.
	www.biocrawler.com /encyclopedia/Sound_power (167 words)

	Standard ECMA-160
		The sound power levels may be used for declaration and comparison purposes (see Standard ECMA-109) for equipment of the same type but from different manufacturers, or of different types.
		The purpose of this measurement procedure is to obtain sound power levels in "controlled" environments using sound intensity procedures with an engineering grade accuracy that is comparable to that of the methods of clauses 5 and 6 of Standard ECMA-74.
		The scanning sound intensity technique in this Standard to determine sound power levels is an alternative to the two procedures in ECMA-74; however, Standard ECMA-74, clause 7 must be used to determine the A-weighted sound pressure level at the bystander or operator position.
	www.ecma-international.org /publications/standards/ECMA-160.htm (623 words)

	Sound Power
		Sound power is the energy rate - the energy of sound per unit of time (J/s, W in SI-units) from a sound source.
		Fans and Sound Power Generation The Sound Power Level from fans depends on the motor power and the capacity of the fan - the static pressure and/or the discharged volume.
		Sound Intensity The sound intensity level is the acoustic power of a sound per unit of area in relation to a fixed reference.
	www.engineeringtoolbox.com /sound-power-level-d_58.html (371 words)

	Selective Level Meter. Shaker. Shunt. Sound Level Meter. Solar Radiation. Standards.Strobe Tachometer.
		Class 2 Sound level generator IEC 942-1988 standards.
		Fast Slow and frequency weighting A. Sound Level Precision Phonometer.
		Sound Level Meter is an integrating sound level meter used for spectral and statistical analysis.
	www.hotektech.com /newproductss.htm (1682 words)

	Sound Level Meter and Vibration Meter Hire UK, Gracey & Associates
		Sound Level Meter and Vibration Meter Hire UK, Gracey and Associates
		Gracey and Associates are an independent organization with over 30 years experience of sound and vibration measurements and applications.
		Bruel and Kjaer - sound transmission meter - RASTI
	www.gracey.com (595 words)

	sound power level- Developer Zone - National Instruments
		sound power level- Developer Zone - National Instruments
		noise power emission level- Developer Zone - National Instruments
		Ten times the common logarithm of the ratio of the acoustic power to the reference sound power, 10
	zone.ni.com /devzone/cda/tut/p/id/2126 (0 words)

	NPL Acoustics: The establishment of a rapid method of making sound power measurements of machinery noise emission
		Sound power determinations have been carried out using 32 noise sources with Directivity Index (DI) ranging from 0.8 dB to 8 dB, in acoustic environments with values of K2A from zero to 9.6 dB.
		The effect on measured sound power levels and on measurement uncertainty of several factors including the number of measurement positions, measurement position orientation relative to source, area and type of enveloping surface, scan distribution and speed and the number of circular, spiral, meridional or rectangular paths, has been assessed.
		It is concluded that the present series of standards describing methods for determining sound power levels of noise sources using sound pressure measurements is inadequate to meet present and foreseen regulatory requirements concerning the noise emission of machinery and equipment.
	www.npl.co.uk /acoustics/publications/articles/546.html (353 words)

	ISVR Consulting - Sound Power Measurement
		A noise level or sound level is usually a sound pressure level, a measure of the small pressure fluctuations in the air superimposed on the normal atmospheric pressure.
		This sound level is important because it relates to the loudness of the sound and to the potential damaging effect on hearing.
		Sound power is measured in watts or picowatts, and sound power levels are traditionally given in decibels (dB re 1pW), where 0 dB corresponds to 1 picowatt.
	www.isvr.co.uk /labtests/swl.htm (667 words)

	ISO - International Organization for Standardization
		ISO 9614-3:2002 specifies a method for measuring the component of sound intensity normal to a measurement surface which is chosen so as to enclose the sound source(s) of which the sound power level is to be determined.
		ISO 9614-3 is not applicable to any frequency band in which the sound power of the source is found to be negative on measurement.
		In such cases the method given in ISO 9614-3 is not suitable for the determination of the sound power level of the source.
	www.iso.org /iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=24012&ICS1=17&ICS2=140&ICS3=1&scopelist=PROGRAMME (418 words)

	Single-Number Descriptors
		For example, a designer can specify that "the background sound level in the Acme theater shall be X," where X is a single-number descriptor conveying the desired quality of sound.
		Ideally, both "A" weighting of sound pressure while displaying all eight octave bands and any A-weighting of sound power (except in accordance with ARI Standard 270) should be avoided.
		To achieve the desired NC level, two layers of sheet rock were added to the duct exterior to sufficiently block the low-frequency sound.
	www.trane.com /commercial/library/vol253/v253e.asp (1130 words)

	Sound power level - Soundpowerlevel
		Sound power level or acoustic power level is a logarithmic measure of the sound power in comparison to a specified reference level.
		The sound power level is given the symbol Lw or SWL and is measured in "dBW", which stands for decibel with the suffix for watts.
		SPL stands for sound pressure level, and is not the same thing.
	www.kopete.org /Sound-power-level.html (82 words)

	Sound power - InformationBlast
		Sound power or acoustic power is a measure of sonic energy E per time t unit.
		It is measured in watts,or sound intensity J times area A: The measure of a ratio of two sound powers is
		Notice: Usable music sound (trumpet) und noise sound (excavator) have both the same sound power of 0.3 watts, but will be judged psycho-acousticly totally different.
	www.informationblast.com /Sound_power.html (125 words)

	NIOSH Topic: Noise and Hearing Loss Prevention: Workplace Solutions: Tools Database: Methods \| CDC/NIOSH
		Power tools and equipment having dimensions that prohibit their testing in the NATF hemi-anechoic chamber are excluded from the database population.
		Some power tools, such as circular saws, are tested in the prescribed full-speed, no-load operating condition, while other tools are tested in the prescribed loaded condition.
		Statistical analysis of the data requires establishing the mean and variance of the sound power level measurement through repetitive testing.
	www.cdc.gov /niosh/topics/noise/workplacesolutions/toolsDatabase_methods.html (725 words)

	Quiet PC USA - Turku Computer Sound Level Assessment Report
		The sound level calibrator was traceably calibrated in June 1998.
		The number value of the sound power level is the same as the sound pressure level at a distance of 30 cm from the point-like sound source in a reverberant-free space.
		The sound pressure level can be calculated from the value of the sound power level when the distance to the sound source is known and the reverberation time of the room is small.
	www.quietpcusa.com /turku.html (1234 words)

	Sound Power - Sydney - NSW - Australia
		the sound power level has been determined by measurements of the sound pressure level of a piece of equipment that needs to be placed during these measurements:
		Based on these measurements, the sound power level of the piece of equipment is determined by the sophisticated analyser.
		Using this system, the sound power level may be determined according to ISO 9614-2 or ANSI S12.12.
	www.pccd.com.au /sound_power.htm (296 words)

	Brüel & Kjær Sound & Vibration
		Sound Power is the most universal of all acoustic metrics.
		Sound Power measurements can be used to make absolute comparisons between different products, predict the sound pressure level in any given environment, and determine acoustic hotspots via sound source ranking.
		Measuring sound power in a reverberation chamber is another common technique that is less expensive than traditional free field techniques.
	www.bkhome.com /bk_template1.asp?spid=194&ctid=90 (308 words)

	NPL Acoustics: Assessment of sound power levels and associated measurement uncertainties of construction equipment
		Thus, it is of prime importance that the sound power level is accurately determined and the level of measurement uncertainty is carefully specified.
		However, it is assumed that absolute sound power levels and associated measurement uncertainties are the same for all measurement configurations.
		Because of the requirement on the manufacturer to affix a label to each machine that displays a guaranteed sound power level that may have to withstand some form of verification procedure, it is important that the sound power level and measurement uncertainty is not affected by the choice of measurement configuration.
	www.npl.co.uk /acoustics/publications/articles/718.html (442 words)

	2.10 What is the sound power level ?
		Sound power level, Lw, is often quoted on machinery to indicate the total sound energy radiated per second.
		For example, a lawn mower with sound power level 88dB(A) will produce a sound level of about 60dB(A) at a distance of 10 metres.
		If the sound power level was 78dB(A) then the lawn mower sound level would be only 50dB(A) at the same distance.
	www.stason.org /TULARC/physics/acoustics-faq/2-10-What-is-the-sound-power-level.html (138 words)

	Decibel
		A unit of a logarithmic scale of power or intensity called the power level or intensity level.
		The result of this logarithmic basis for the scale is that increasing a sound intensity by a factor of 10 raises its level by 10 dB; increasing it by a factor of 100 raises its level by 20 dB; by 1,000, 30 dB and so on.
		When two sound sources of equal intensity or power are measured together, their combined intensity level is 3 dB higher than the level of either separately.
	www.sfu.ca /sonic-studio/handbook/Decibel.html (447 words)

	Sound Pressure Level and Power
		Because of the wide range, sound pressure measurements are made on a logarithmic scale (decibel scale).
		SPL is proportional to the average squared amplitude.
		Total sound power emitted by a source in all directions.
	ccrma.stanford.edu /CCRMA/Courses/152/SPL.html (105 words)

	WK8183- Standard Test Method for Determining A-Weighted Sound Power Level of Central Vacuum Power Units
		To establish and document an accurate test method to determine the sound power level of a central vacuum at the power unit location.
		This test method calculates the overall A-weighted sound power level emmitted by central vacuum power units, intended for operation in domestic applications.
		To test the sound power level of a central vacuum at the User's location, refer to the ASTM standard F1334.
	www.astm.org /DATABASE.CART/WORKITEMS/WK8183.htm (164 words)

	Daikin air conditioning - Sound power Sound pressure
		Is a measure of the sound energy emitted from a source of noise, expresses in decibel or dBA
		The sound power level can be considered as the more precise of the two.
		The sound power will have a higher value than the sound pressure, bon't be mislead by this.
	www.daikineurope.com /faq/items/power-pressure.jsp (65 words)

	The Lawnmowers (Harmonization of Noise Emission Standards) Regulations 1992
		"EEC sound power level mark" means a mark in the form set out in Schedule 2A which indicates the maximum sound power level of a lawnmower expressed in dB(A)/pW as guaranteed by the manufacturer and as certified in the certificate of conformity issued in respect of that lawnmower;
		"permissible sound power level" means the sound power level specified in the second column of the Table in Schedule 4 in respect of a lawnmower with the cutting width specified in the first column of that Table;
		(a) the sound power level does not exceed the permissible sound power level for that lawnmower and, in the case of a wide lawnmower, the sound pressure level does not exceed the permissible sound pressure level;
	www.opsi.gov.uk /si/si1992/Uksi_19920168_en_1.htm (1527 words)

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